Micro-ros topic visible but no data is published

[DimitriBosch]

Topics do not publish any data

Hi all,

I am trying to get the micro_ros_publisher example to work, but I am encountering two issues:

1. When setting up the agent (ros2 run micro_ros_agent micro_ros_agent serial --dev /dev/ttyACM0), the process often doesn't get past the "create_topic" or "create_publisher" stage. The output differs each time I try setting up the agent.
2. When it successfully creates a datawriter ("datawriter created") the topic name shows up with ros2 topic list (/micro_ros_arduino_node_publisher) but when I try to view it (using ros2 topic echo) it doesn't give me any output.

Steps to reproduce the issue

I have a Raspberry Pi 4 connected to a Teensy 4.0 board using a USB cable. Regarding software, I'm using the following versions:

• Ubuntu 22.04 + ROS2 Humble
• Arduino IDE 2.3.6
• Teensyduino 1.57.3

I've installed micro-ros on my RPi following the official instructions (https://micro.ros.org/docs/tutorials/core/first_application_linux/). The teensy is included in my Arduino IDE with the precompiled v2.0.8-humble micro-ros release. I have also applied the teensy patch to ensure compatibility.

Actual behaviour

The image below shows the output of some commands within the ros 2 workspace.

Expected behaviour

The arduino script should continuously output integers in ascending order.

Some help would be greatly appreciated!

[hippo5329]

You can switch to platformio and follow this guide.

https://github.com/hippo5329/micro_ros_arduino_examples_platformio/wiki

[DimitriBosch]

You can switch to platformio and follow this guide.

https://github.com/hippo5329/micro_ros_arduino_examples_platformio/wiki

Unfortunately, using platformio gives me the same issues.

[hippo5329]

@DimitriBosch I made a fresh install of ubuntu 22.04 on rpi4. It works without issues.

Do not follow the official instructions and do not use micro ros setup. Follow my wiki.

[DimitriBosch]

It is solved now; I downgraded my micro_ros_arduino library to 2.0.7-humble (directly within Arduino IDE). I was initially using 2.0.8-humble, imported as a .zip file.